Thank you for your help. It seems that I'm unable to write to the msi message control register in order to enable MSIs in my 1040 which is set up at the Root. Any idea why this would be the case? I am also reading 0s in the MSI message capability id register which it says is supposed to be 0x05.

sorry I mistyped that second register, it is the PEX_CONFIG_DATA register. The ADDR register is: 0xFE250000 DATA is: 0xFE250004. The offsest of 0x250000 is because we are using the PEX2 controller. I'm not sure what the RCW is that you are referring to, it you could please explain.

ok, that's what I needed to know. I guess I'm just not sure what other things i need to configure on the RC side. I am setting the IWBAR and IWBEAR to the same address which our device is sending it's MSIs to. I also set the PEXMSIIWAR to 0x80E00000. Is there any additional configuration necessary?